Method and device for assigning a blood plasma sample

ABSTRACT

A device and method for assigning a blood plasma sample to a class from a predetermined set of classes are presented. The set of classes comprises a good class, a lipemic class, a hemolytic class and an icteric class. For assignment to one of the classes, the blood plasma sample is exposed to light and measurement values dependent on transmitted or scattered light power are evaluated in order to carry out an assignment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of patent application Ser. No.15/234,511, filed on Aug. 11, 2016, now allowed, which is a continuationof PCT/EP2015/053131, filed Feb. 13, 2015, which is based on and claimspriority to EP 14155821.3, filed Feb. 19, 2014, which are herebyincorporated by reference.

BACKGROUND

The present disclosure relates to a method and a device for assigning ablood plasma sample to a class from a predetermined set of classes,where the blood plasma sample is contained in an at least partiallytransparent vessel.

Blood samples are often used in order to be able to diagnose particularillnesses or, alternatively, in order to be able to detect criminaloffences or infringements of regulations such as, for example, theconsumption of drugs or driving under the influence of alcohol. Such ablood sample is typically introduced into a light-transparent vessel inthe form of a plastic tube, such a tube being configured in a similarway to a test tube. In the tube, the sample is typically centrifugedbefore further analysis steps, so that a blood precipitate, in which allthe cellular constituents of the blood sample are concentrated, isformed at the lower end of the tube. Above the blood precipitate, thereis then typically blood plasma which essentially contains the liquidconstituents of the blood sample. The blood plasma, which forms a bloodplasma sample, is generally analyzed in subsequent analysis steps.

Often, before further analysis steps, it is expedient to carry out atleast a rough determination of whether the blood plasma sample indicatesa particular pathological state, or has particular features in anotherway. To this end, the blood plasma sample may be assigned to a classfrom a predetermined set of classes, such assignment generally beingcarried out manually. This is in particular because blood plasma samplesare usually provided with extensive labels which indicate data such asthe name of the patient or the date of the sampling. However, suchlabels prevent the transparency of the vessel from being utilized inorder to carry out preliminary analysis of the blood plasma sample byoptical methods.

Typical classes assigned to a blood plasma sample at the stage relevanthere are, for example, a lipemic class, a hemolytic class, an ictericclass and a good class. The “good” class contains those samples whichare not assigned to the class lipemic, hemolytic or icteric.

When the sample is to be assigned to the lipemic class, it is a lipemicsample which has an elevated level of lipids. This may, for example, bean indication of a disorder of the fat metabolism.

When the sample is to be assigned to the hemolytic class, it is ahemolytic sample which has an elevated level of hemoglobin. This may,for example, be an indication of particular anemias, transfusionreactions or malaria.

When the blood plasma sample is to be assigned to the icteric class, itis an icteric sample which has an elevated level of bilirubin. This may,for example, be an indication of a disease of the liver.

There is a need for a device and method for assigning a blood plasmasample to a class of predetermined set of classes that allows automatedassignment even in the case of labeled vessels.

SUMMARY

According to the present disclosure, a device and method for assigning ablood plasma sample to a class from a predetermined set of classes arepresented. The blood plasma sample can be contained in an at leastpartially transparent vessel. The method can comprise exposing the bloodplasma sample to light. The spectral composition of the light cancomprise at least wavelengths from a predetermined set of wavelengths.The method can further comprise forming a wavelength-specificmeasurement value for a respective wavelength from the set ofwavelengths. A respective measurement value can be dependent on a lightpower transmitted through the blood plasma sample and the vessel at therespective wavelength. The method can further comprise assigning theblood plasma sample to a class as a function of the wavelength-specificmeasurement values. The predetermined set of classes can comprise ahemolytic class. The set of wavelengths can comprise a first hemolyticwavelength in the range of from 535 nm to 547 nm and a second hemolyticwavelength in the range of from 510 nm to 520 nm and the blood plasmasample can be assigned to the hemolytic class if a ratio of themeasurement value at the first hemolytic wavelength and the measurementvalue at the second hemolytic wavelength is less than a first relativehemolytic threshold value.

Accordingly, it is a feature of the embodiments of the presentdisclosure to provide a device and method for assigning a blood plasmasample to a class of predetermined set of classes that allows automatedassignment even in the case of labeled vessels. Other features of theembodiments of the present disclosure will be apparent in light of thedescription of the disclosure embodied herein.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The following detailed description of specific embodiments of thepresent disclosure can be best understood when read in conjunction withthe following drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1 illustrates typical transmission spectra in the visiblewavelength range for different classes of samples according to anembodiment of the present disclosure.

FIG. 2 illustrates a device for assigning a blood plasma sample, whichcarries out a method for assigning a blood plasma sample to a classaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description of the embodiments, reference ismade to the accompanying drawings that form a part hereof, and in whichare shown by way of illustration, and not by way of limitation, specificembodiments in which the disclosure may be practiced. It is to beunderstood that other embodiments may be utilized and that logical,mechanical and electrical changes may be made without departing from thespirit and scope of the present disclosure.

A method for assigning a (e.g., blood plasma) sample to a class from apredetermined set of classes is presented. The blood plasma sample,optionally together with other layer-wise arranged constituents such asblood precipitate, separating gel, and the like can be contained in an,at least, partially transparent vessel. The method can comprisesexposing the blood plasma sample to light, the spectral composition ofwhich can comprise at least wavelengths from a set of differentwavelengths, forming a wavelength-dependent measurement value for arespective wavelength from the set of wavelengths, a respectivemeasurement value can be dependent on a light power, transmitted throughthe blood plasma sample and the vessel, or transmitted light intensityat the respective wavelength, and assigning the blood plasma sample to aclass as a function of the wavelength-specific measurement values.

The predetermined set of classes can comprise a hemolytic class. The setof wavelengths can comprise a first hemolytic wavelength in the rangefrom about 535 nm to about 547 nm. In one embodiment, the firsthemolytic wavelength can be 541 nm. The set of wavelengths can alsocomprise a second hemolytic wavelength in the range from about 510 nm toabout 520 nm. In one embodiment, the second hemolytic wavelength can be515 nm. The blood plasma sample can be assigned to the hemolytic classwhen a ratio of the measurement value at the first hemolytic wavelengthand the measurement value at the second hemolytic wavelength is lessthan a first relative hemolytic threshold value.

This procedure can be based on the transmission at a wavelength of about515 nm being influenced only little by hemoglobin. The measurement valueat this wavelength can therefore be used as a reference for themeasurement value at a wavelength of about 541 nm. In contrast todetermination by comparison of the absolute value of the measurementvalue with an absolute hemolytic threshold value, in the comparison justdescribed of a ratio, i.e. a relative value, with the relative hemolyticthreshold value, it may not be necessary to rule out it being a lipemicsample, in order to be able to determine reliably a hemolytic sample.This can be because a particularly low ratio of the measurement value atthe first hemolytic wavelength and the measurement value at the secondhemolytic wavelength can occur only in hemolytic samples.

The ratio of the measurement value at the first hemolytic wavelength andthe measurement value at the second hemolytic wavelength may becalculated as follows:

ti V=M1/M2,

where V denotes the ratio of the measurement values, M1 denotes themeasurement value at the first hemolytic wavelength and M2 denotes themeasurement value at the second hemolytic wavelength. M2 is consequentlyused as a reference (value).

The following applies for the assignment to the hemolytic class:V<Swhere S denotes the first relative hemolytic threshold value.

The first relative hemolytic threshold value S may be less than about 1.In another embodiment the first relative hemolytic threshold value S canbe less than 0.75. In yet another embodiment, the first relativehemolytic threshold value S can be less than 0.5.

Contrary to the prior art, the present disclosure is based on it beingpossible to carry out assignment of the blood plasma sample bytransmitted light even if there is a label on the vessel. By thismethod, reliable and rapid automatic testing of blood plasma samples canbe possible, which can make it possible to use the method in an analysissystem configured for high throughput.

During the formation of a wavelength-specific measurement value, eitherprecisely one wavelength-specific measurement value may be formed or aplurality of wavelength-specific measurement values at the samewavelength may be formed, an average value of the measurement valuesbeing, for example, formed.

The respective measurement value may be dependent on a light powertransmitted in a straight line through the blood plasma sample and thevessel. In this case, determination is carried out of which fraction ofthe light emitted on one side passes in a straight line through thesample and which fraction is absorbed inside the sample, or elsescattered. This information may be used in order to assign the bloodplasma sample to a class.

According to one embodiment, the predetermined set of classes cancomprise a lipemic class. The set of wavelengths can comprise a lipemicwavelength in the range from about 610 nm to about 700 nm. In oneembodiment, the lipemic wavelength can be 650 nm or 685 nm. The bloodplasma sample can be assigned to the lipemic class when the measurementvalue at the lipemic wavelength is less than a lipemic threshold value.

This embodiment can be based on the fact that lipids can reduce thetransmission through the blood plasma sample particularly in the rangefrom about 610 nm to about 700 nm and especially at 650 nm and at 685nm. Therefore, a lipemic sample can be detected by comparing thecorresponding measurement value with a suitably selected lipemicthreshold value.

According to one embodiment, the predetermined set of classes cancomprise a lipemic class. A scattering measurement value can be formed,which can be dependent on a light power, scattered by the blood plasmasample, or scattered light intensity, the blood plasma sample beingassigned to the lipemic class when the scattering measurement value isgreater than a lipemic scattering threshold value. This scatteringmeasurement may be combined with the transmission measurement. Thescattering measurement value may be dependent on a light power scatteredlaterally, for example, at an angle of about 90° relative totransmission in a straight line. This may, for example, be achieved byarranging a corresponding detector.

The scattering measurement value may be dependent on an elasticallyscattered light power or on an elastically scattered light intensity. Inthis context, elastically means that the lipemic wavelength remainsconstant throughout the scattering process.

The detection of a lipemic sample with the aid of such a scatteringmeasurement value is based on the discovery that lipids scatter certainwavelengths particularly strongly. This does not apply for any of theother substances relevant here to be determined in the blood plasmasample. The use of a scattering measurement value can therefore besuitable for the detection of a lipemic sample.

According to one embodiment, the blood plasma sample can be assigned tothe hemolytic class when the measurement value at the first hemolyticwavelength is less than an absolute hemolytic threshold value and whenthe blood plasma sample is not assigned to a lipemic class.

This embodiment is based on the transmission in the case of a samplecontaining hemoglobin being low at a wavelength of about 541 nm, whichmay in principle be used for the detection of a hemolytic sample. In thecase of a high lipid content, however, a lipemic sample likewise canhave only a low transmission at the aforementioned wavelength. Onlyconsidering the measurement value at a wavelength of about 541 nm cantherefore not be sufficient in order to detect a hemolytic samplereliably. The blood plasma sample can therefore be assigned to thehemolytic class on the basis of a comparison of the absolute value ofthe measurement value with the absolute hemolytic threshold value onlyif it can be ensured that it is not a lipemic sample. Since, asdescribed above, a lipemic sample can be detected reliably at muchlonger wavelengths or by scattered light, in this way it can be possibleto distinguish hemolytic, lipemic and good samples from one anotherreliably. It can be mentioned that the establishment that it is not alipemic sample need not necessarily be based on the disclosed method andnot necessarily on an optical measurement. It may, for example, also beensured by external factors that lipemic samples do not reach the pointat which the method is carried out, for example by an upstream sortingdevice or because samples come only from a particular hospitaldepartment.

According to one embodiment, the set of wavelengths can comprise a thirdhemolytic wavelength in the range of about 610 nm to about 700 nm. Inone embodiment, the third hemolytic wavelength can be 650 nm or 685 nm.The blood plasma sample can be assigned to the hemolytic class when aratio of the measurement value at the first hemolytic wavelength and themeasurement value at the third hemolytic wavelength is less than asecond relative hemolytic threshold value.

This embodiment is based on the fact that a measurement value at awavelength from about 610 nm to about 700 nm may also be used as areference value instead of the above-described wavelength of about 515nm. A particularly low value of the described ratio of the measurementvalue at the first hemolytic wavelength and the measurement value at thethird hemolytic wavelength can occur only in the case of a hemolyticsample so that this ratio may also be used reliably on its own for thedetection of a hemolytic sample. It can be mentioned that themeasurement value at the third hemolytic wavelength can be particularlylow in the case of a lipemic sample so that the ratio described here canincrease.

The ratio of the measurement value at the first hemolytic wavelength andthe measurement value at the third hemolytic wavelength may becalculated as follows:V2=M1/M3,where V2 denotes the ratio of the measurement values, M1 denotes themeasurement value at the first hemolytic wavelength and M3 denotes themeasurement value at the third hemolytic wavelength. M3 is consequentlyused as a reference (value).

The following applies for the assignment to the hemolytic class:V2<S2where S2 denotes the second relative hemolytic threshold value.

The second relative hemolytic threshold value S2 may be less thanabout 1. In another embodiment, the second relative hemolytic thresholdvalue S2 may be less than 0.25. In yet another embodiment, the secondrelative hemolytic threshold value S2 may be less than 0.1.

According to one embodiment, the predetermined set of classes cancomprise an icteric class. The set of wavelengths can comprise a firsticteric wavelength in the range from about 450 nm to about 485 nm. Inone embodiment, the first icteric wavelength can be 470 nm. The bloodplasma sample can be assigned to the icteric class when the measurementvalue at the first icteric wavelength is less than an absolute ictericthreshold value and when the blood plasma sample is not assigned to alipemic class and is not assigned to a hemolytic class.

This procedure can be based on the fact that a particularly lowtransmission in the range from about 450 nm to about 485 nm such as, forexample, at about 470 nm, can occur in icteric samples because of thebilirubin contained. A low transmission in this wavelength range mayhowever also occur in lipemic samples or in hemolytic samples,especially in the case of a particularly high concentration of lipids orhemoglobin. It can therefore be preferable to assign a blood plasmasample to the icteric class on the basis of a comparison of the absolutevalue of the measurement value at the first icteric wavelength with theabsolute icteric threshold value only if it can be ruled out that it isa lipemic sample or a hemolytic sample. This may, as described above, bedone outside the range from about 450 nm to about 485 nm. In this way,icteric, hemolytic, lipemic and good samples can be distinguishedreliably from one another.

In this case as well, it can be possible to rule out by externalmeasures, as described above, that it is a lipemic sample or a hemolyticsample.

According to one embodiment, the predetermined set of classes cancomprise an icteric class. The set of wavelengths can comprise a firsticteric wavelength in the range from about 450 nm to about 485 nm suchas, for example, 470 nm and a second icteric wavelength in the rangefrom about 510 nm to about 520 nm such as, for example, 515 nm. Theblood plasma sample can be assigned to the icteric class when a ratio ofthe measurement value at the first icteric wavelength and themeasurement value at the second icteric wavelength is less than a firstrelative icteric threshold value. The first relative icteric thresholdvalue may, for example, be about 0.1.

This procedure can be based on the fact that the transmission through ablood plasma sample in the range from about 510 nm to about 520 nm suchas, for example at 515 nm, may be used as a reference for thedetermination of an icteric sample, in the same way as was alreadyexplained above with reference to a hemolytic sample. A separatesafeguard that it is not a hemolytic or lipemic sample may be omitted,because a particularly low ratio of the measurement value at the firsticteric wavelength and the measurement value at the second ictericwavelength can occurs only in the case of an icteric sample.

The second icteric wavelength may be equal to the second hemolyticwavelength. This can be favorable when the predetermined set of classescomprises both an icteric class and a hemolytic class, since onewavelength may then be used for the assignment to both classes. Outlayon apparatus can thereby be reduced.

According to one embodiment, the predetermined set of classes cancomprise an icteric class. The set of wavelengths can comprise a firsticteric wavelength in the range from about 450 nm to about 485 nm suchas, for example, 470 nm, and a third icteric wavelength in the rangefrom about 610 nm to about 700 nm such as, for example, 650 nm or 685nm. The blood plasma sample can be assigned to the icteric class when aratio of the measurement value at the first icteric wavelength and themeasurement value at the third icteric wavelength is less than a secondrelative icteric threshold value. The second relative icteric thresholdvalue may, for example, be about 0.1.

This procedure can be based on the fact that the wavelength range fromabout 610 nm to about 700 nm, and in particular 650 nm or 685 nm, maylikewise be used as a reference for the determination of an ictericsample like the above-described wavelength range from about 510 nm toabout 520 nm. This can rely on the fact that the measurement value inthis wavelength range is not reduced, or is reduced only little, in anicteric sample.

The third icteric wavelength may be equal to the third hemolyticwavelength. This can be favorable in particular when the set of classescomprises both an icteric class and a hemolytic class. As alreadydescribed above, outlay on apparatus can be reduced by such a procedure.

According to one embodiment, the predetermined set of classes cancomprise a good class. The blood plasma sample can be assigned to thegood class when the blood plasma sample is not assigned to a lipemicclass, is not assigned to a hemolytic class and is not assigned to anicteric class.

The described procedure may mean that, for a sample, a check can be madeas to whether it is a lipemic sample, whether it is a hemolytic sampleand whether it is an icteric sample. Only when it is established that itis not a lipemic sample, not a hemolytic sample, and not an ictericsample, can the blood plasma sample be assigned to the good class. Itmay, however, also mean that one or two of the described classes are notchecked, and therefore the blood plasma sample can already be assignedto the good class when it is established that it is not one of thechecked classes of samples. This may for example be favorable when, dueto influencing factors which lie outside a testing system used forcarrying out the method, i.e. by external measures, it can be ensured orat least unlikely that a particular class of samples occurs, or eventhat two particular classes of samples occur.

According to one embodiment, an error message can be emitted when theblood plasma sample is assigned to at least two different classes. Anerror message may, for example, be an acoustic warning sound and/or anerror indication on a display. This can accommodate the fact that forthis case it is likely that at least one detection method for aparticular class of samples has failed and manual determination of theclass of the blood plasma sample or termination of further analysissteps may be advisable.

According to one embodiment, the method can comprise detecting whether,and also at what position, there is a label on the vessel, a number ofthreshold values being modified as a function thereof. Under certaincircumstances, rotation of the sample may also be carried out in such away that the transmitted light needs to pass through as few label layersas possible.

This can accommodate the fact that the transmission at all wavelengthscan be modified when a light beam used for the measurement passesthrough this label. In this case, it can also be possible to distinguishwhether the light beam passes through the label only on entry or onexit, or both on entry and on exit. By the adaptation of thresholdvalues as a function of such detection, the reliability of the methodwhich carries out an assignment of the sample to a class on the basis ofthe comparison with such a threshold value can be increased.

In principle, all threshold values used may be modified. It can also bepossible to modify a subgroup of the threshold values used. Inparticular, the threshold values described above may be modified.

It may be expedient to modify the absolute threshold values, since inthe case of a comparison of absolute values there is no correction by areference value which would likewise be subject to the influence of thelabel. One threshold value or a plurality of threshold values, from thegroup of threshold values which can comprise of the absolute lipemicthreshold value, the lipemic scattering threshold value, the absolutehemolytic threshold value and the absolute icteric threshold value, maytherefore be modified. Likewise, however, the relative threshold valuesmay also be modified, i.e. for example one threshold value or aplurality of threshold values from the group of threshold values whichcan comprise of the first relative hemolytic threshold value, the secondrelative hemolytic threshold value, the first relative icteric thresholdvalue and the second relative icteric threshold value.

According to one refinement, it can also be possible to detect whetherthe light beam passes through a plurality of labels, i.e. not justthrough one label. The aforementioned threshold values may also bemodified in a suitable way as a function thereof.

The described modification of threshold values can be especiallyadvantageous when a comparatively low light power is used. In the caseof high light powers, the influence of labels may also be sufficientlylow, so that the modification of threshold values may be omitted.

The step of detecting whether, and also at what position, there is alabel on the vessel can be carried out by a camera. It can however alsobe possible to use other measuring instruments such as, for example aphotodetector.

A device for assigning a blood plasma sample contained in an at leastpartially transparent vessel, by using the aforementioned method is alsopresented. The device can comprise a light source which can emit light,the spectral composition which can comprise at least one wavelength fromthe predetermined set of wavelengths according to the method, onto thevessel, a detector arrangement, which can receives light transmitted (ina straight line) through the blood plasma sample and the vessel and candetermine therein a measurement value dependent on the transmitted lightpower or the transmitted light intensity for each of the wavelengthsfrom the set of wavelengths, and a control device, which can beconnected to the detector arrangement in order to record the measuredmeasurement values and can be configured to carry out the disclosedmethod. The control device may, for example, be a conventional personalcomputer on which a program on which the disclosed method is run.

The method can be carried out using such a device. The device thereforecan make it possible to detect the class of a blood plasma sample, or inother words, to assign a blood plasma sample to a class, without manualintervention being necessary therefor, even if there is a label on thevessel.

When carrying out the disclosed method with the disclosed device, allabove-described configurations of the method may be employed in anydesired combination. The advantages explained apply accordingly.

According to one embodiment, the detector arrangement can comprise, foreach wavelength from the set of wavelengths, a detector, a filterarranged upstream of the detector, and a light-guiding fiber forreceiving light transmitted through the sample and the vessel.

A detector may, for example, be a conventional photodetector such as,for example, a semiconductor detector.

The filter may, for example, be an optical filter or an interferencefilter. Such a filter conventionally can have only a narrow transmissionrange, so that a wavelength range of only one or only a few nanometerscan be transmitted in a narrowband through the filter. Such filters mayalso be referred to as bandpass filters. It can therefore be possible todetermine the wavelength, or the wavelength range, from which thedownstream detector records a measurement value.

The use of light-guiding fibers can allow reliable light guiding to aposition at which a detector is located, which can increase the freedomin arranging the detectors. Furthermore, it can therefore readily bepossible to use a plurality of detectors, which can be problematic if itis necessary to fit detectors directly on the vessel.

The device may comprise a further detector arrangement, which canreceive light scattered laterally such as, for example, with an angle ofabout 90°, by the blood plasma sample relative to propagation in astraight line, and can determine a further measurement value dependenton the scattered light power or the scattered light intensity, thecontrol device being connected to the further detector arrangement inorder to record the further measurement value.

It can therefore be possible to carry out a method based on themeasurement of scattered light, as was explained above with reference tothe assignment of a blood plasma sample to the lipemic class.

The control device may, for example, be a conventional computer oranother electronic device having a processor, a storage medium andsuitable interfaces.

The device may comprise a camera with which labels on the vessel can bedetected. To this end, suitable known image recognition algorithms maybe used. This can be suitable for the above-described variation ofthreshold values as a function of whether a light beam passes through alabel or through a plurality of labels.

Referring initially to FIG. 1, FIG. 1 shows a typical, schematicallyrepresented transmission spectra of good, icteric, hemolytic and lipemicsamples. The wavelength (λ) in the range from about 450 nm to about 700nm, i.e. approximately in the visible spectrum, can be represented inthis case on the horizontal axis. The transmission (T) in values fromabout 0% to about 100% can be represented on the vertical axis.

The solid curve shows a typical transmission spectrum of a good sample.It can be seen that the value of the transmission rises from about 0% to100% over the wavelength range shown from about 450 nm to about 700 nm.Between about 550 nm and about 600 nm, the curve can be structured,specifically with a maximum and a minimum.

The dashed curve shows a typical transmission spectrum of an ictericsample. It can be seen that, in the range below about 600 nm, thetransmission lies below that of a good sample. This may be used in orderto detect an icteric sample. In particular, the value of thetransmission at a wavelength of about 470 nm is less than in the case ofa good sample.

The dotted curve shows a typical transmission spectrum of a hemolyticsample. It can be seen that the transmission in such a hemolytic sampleessentially lies below the transmission of a good sample. Furthermore,such a hemolytic sample can have an additional minimum in thetransmission curve at a wavelength of about 541 nm (as well as at about580 nm). This may be used in order to detect such a hemolytic sample.

The curve represented in dots and dashes shows a typical transmissionspectrum of a lipemic sample. It can be seen that the transmission insuch a lipemic sample lies essentially below the transmission of a goodsample. In particular, this applies to the range from about 610 nm toabout 700 nm, which may be used in order to detect such a lipemicsample.

FIG. 2 shows a device 10 for assigning a blood plasma sample to a classfrom a predetermined set of classes. The device 10 can comprise a lightsource in the form of a halogen lamp 20, which can emit a light beam 25with a broadband spectrum. The term light beam can also include splitbeams.

The device 10 can comprise a sample holder 30, in which an at leastpartially transparent vessel 35 can be received. In the vessel 35, therecan be a centrifuged blood sample, or blood plasma sample.

The light beam 25 can strike the vessel 35 and can pass through thevessel 35. The vessel 35 can be oriented with respect to the lightsource 20 in such a way that the light beam 25 can pass through theblood plasma.

Provided opposite the halogen lamp 20, next to the sample holder 30,there can be a light collector 40 which can receive that part of thelight beam 25 that is transmitted through the vessel 35, and thereforealso through the sample. Light-guiding fibers in the form of a firstglass fiber cable 41, a second glass fiber cable 42, a third glass fibercable 43 and a fourth glass fiber cable 44 can extend from the lightcollector 40.

The first glass fiber cable 41 can lead to a first bandpass filter 51,behind which there can be a first photodiode 61. The second glass fibercable 42 can lead to a second bandpass filter 52, behind which there canbe a second photodiode 62. The third glass fiber cable 43 can lead to athird bandpass filter 53, behind which there can be a third photodiode63. The fourth glass fiber cable 44 can lead to a fourth bandpass filter54, behind which there can be a fourth photodiode 64.

In addition, a further photodiode 60, which can detect scattered light,can be arranged laterally with respect to the path of the light beam 25.Together, the light collector 40, the glass fiber cables 41, 42, 43, 44,the bandpass filters 51, 52, 53, 54, the further photodiode 60 and thefirst, second, third and fourth photodiodes 61, 62, 63, 64 can form adetector arrangement 65. It can be understood that further glass fibercables and associated photodiodes may be provided for correspondingfurther wavelengths.

The device 10 can furthermore comprise a camera 68 to record the vessel35 in the sample holder 30. In this way, for example, a label and aposition of the label on the vessel 35 can be detected.

The photodiodes 60, 61, 62, 63, 64 and the camera 68 can be connected toan electronic control device 70. The latter can record signals of thephotodiodes 60, 61, 62, 63, 64 and of the camera 68, in order to assignthe sample contained in the vessel 35 to a class from a set ofpredetermined classes by the disclosed method. These classes can be alipemic class, a hemolytic class, an icteric class and a good class.

The first bandpass filter 51 can have a transmission maximum at 685 nmcorresponding to a lipemic wavelength. If a measurement value determinedby the first photodiode 61 is less than a predetermined lipemicthreshold value, the electronic control device 70 can assign the sampleto the lipemic class. Furthermore, the sample can likewise be assignedto the lipemic class when a measurement value of the further photodiode60 detecting scattered light is greater than a lipemic scatteringthreshold value. If the two described possibilities for assigning thesample to the lipemic class lead to different results, an error messagecan be emitted.

The second bandpass filter 52 can have a transmission maximum at 541 nmcorresponding to a first hemolytic wavelength. If a measurement valuedetected by the second photodiode 62 is less than a predeterminedabsolute hemolytic threshold value, and if at the same time the samplehas not been assigned to the lipemic class, the electronic controldevice 70 can assign the sample to the hemolytic class. Furthermore, theelectronic control device 70 can also calculate a ratio of themeasurement values measured by the second detector 62 and the firstdetector 61. If this ratio is less than a relative hemolytic thresholdvalue, the electronic control device 70 can likewise assign the sampleto the hemolytic class. If the two described possibilities for assigningthe sample to the hemolytic class lead to different results, an errormessage can be emitted.

The third bandpass filter 53 can have a transmission maximum at 515 nmcorresponding to a second icteric wavelength. The fourth bandpass filter54 can have a transmission maximum at 470 nm corresponding to a firsticteric wavelength. If a measurement value measured by the fourthphotodiode 64 is less than an absolute icteric threshold value, and ifat the same time the blood plasma sample is assigned neither to thelipemic class nor to the hemolytic class, the electronic control device70 can assign the sample to the icteric class. Furthermore, theelectronic control device 70 can also calculate a ratio of themeasurement values measured by the fourth detector 64 and the thirddetector 63. If this ratio is less than a relative icteric thresholdvalue, the electronic control device 70 can likewise assign the sampleto the icteric class. If the two described possibilities for assigningthe sample to the icteric class lead to different results, an errormessage can be emitted.

If the control device 70 does not assign the sample to the lipemicclass, to the hemolytic class or to the icteric class, it can assign thesample to the good class.

By an image delivered by the camera 68, the electronic control device 70can determine whether the light beam 25 can travel unimpeded on its paththrough the vessel 35 and the sample contained therein, or the bloodplasma contained therein, or whether it has to pass through one or morelabels. Unimpeded travel can be intended to mean that the light beam 25passes only through the sample, or the blood plasma contained therein,and through transparent parts of the vessel 35. As a function thereof,the electronic control device 70 can modify the aforementioned thresholdvalues in a predetermined way. In particular, when it has beendiscovered that the light beam 25 has to pass through at least onelabel, the absolute threshold values can be reduced since in this case,the light beam is partially absorbed by the label.

By the assignment of the sample to a class, carried out in the controldevice 70, subsequent analysis steps may be simplified or plannedbetter. If an error message is emitted, manual intervention may beinitiated in order to prevent incorrect analyses.

It is noted that terms like “preferably,” “commonly,” and “typically”are not utilized herein to limit the scope of the claimed embodiments orto imply that certain features are critical, essential, or evenimportant to the structure or function of the claimed embodiments.Rather, these terms are merely intended to highlight alternative oradditional features that may or may not be utilized in a particularembodiment of the present disclosure.

Having described the present disclosure in detail and by reference tospecific embodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of thedisclosure defined in the appended claims. More specifically, althoughsome aspects of the present disclosure are identified herein aspreferred or particularly advantageous, it is contemplated that thepresent disclosure is not necessarily limited to these preferred aspectsof the disclosure.

We claim:
 1. A device for assigning a blood plasma sample to a classfrom a predetermined set of classes, the blood plasma sample beingcontained in an at least partially transparent vessel, the devicecomprising: a light source configured to emit light, the spectralcomposition of which comprises at least wavelengths from a predeterminedset of wavelengths, onto the vessel; a detector arrangement configuredto receive light transmitted through the blood plasma sample and thevessel and to measure therein a measurement value dependent on thetransmitted light power for each of the wavelengths from the set ofwavelengths; and a control device connected to the detector arrangementin order to record the measurement values and configured to assign theblood plasma sample to a class as a function of the recorded measurementvalues, wherein the predetermined set of classes comprises a hemolyticclass, wherein the set of wavelengths comprises a first hemolyticwavelength in the range of from 535 nm to 547 nm and a second hemolyticwavelength in the range of from 510 nm to 520 nm, and wherein the bloodplasma sample is assigned to the hemolytic class if a ratio of themeasurement value at the first hemolytic wavelength and the measurementvalue at the second hemolytic wavelength is less than a first relativehemolytic threshold value.
 2. The device according to claim 1, whereinthe detector arrangement comprises, for each wavelength from the set ofwavelengths, a detector, a filter arranged upstream of the detector, anda light-guiding fiber for receiving light transmitted through the sampleand the vessel.
 3. The device according to claim 1, further comprising,a further detector configured to receive light scattered laterally bythe blood plasma sample relative to propagation in a straight line andto measure a measurement value dependent on the scattered light power,wherein the control device is connected to the further detector in orderto record the measured measurement value.
 4. The device according toclaim 3, wherein the further detector receives light scattered laterallyat an angle of 90° relative to transmission in a straight line.
 5. Thedevice according to claim 1, wherein the first hemolytic wavelength is541 nm.
 6. The device according to claim 1, wherein the second hemolyticwavelength is 515 nm.
 7. The device according to claim 1, wherein thepredetermined set of classes comprises a lipemic class, the set ofwavelengths comprises a lipemic wavelength in the range of from 610 nmto 700 nm, and the blood plasma sample is assigned to the lipemic classif the measurement value at the lipemic wavelength is less than alipemic threshold value.
 8. The device according to claim 7, wherein thelipemic wavelength is 650 nm or 685 nm.
 9. The device according to claim3, wherein the predetermined set of classes comprises a lipemic classand a scattering measurement value is formed dependent on a light powerscattered by the blood plasma sample, wherein the blood plasma sample isassigned to the lipemic class if the scattering measurement value isgreater than a lipemic scattering threshold value.
 10. The deviceaccording to claim 1, wherein the blood plasma sample is assigned to thehemolytic class if the measurement value at the first hemolyticwavelength is less than an absolute hemolytic threshold value and if theblood plasma sample is not assigned to a lipemic class.
 11. The deviceaccording to claim 1, wherein the set of wavelengths comprises a thirdhemolytic wavelength in the range of from 610 nm to 700 nm and the bloodplasma sample is assigned to the hemolytic class if a ratio of themeasurement value at the first hemolytic wavelength and the measurementvalue at the third hemolytic wavelength is less than a second relativehemolytic threshold value.
 12. The device according to claim 11, whereinthe third hemolytic wavelength is 650 nm or 685 nm.
 13. The deviceaccording to claim 1, wherein the predetermined set of classes comprisesan icteric class, the set of wavelengths comprises a first ictericwavelength in the range of from 450 nm to 485 nm, and the blood plasmasample is assigned to the icteric class if the measurement value at thefirst icteric wavelength is less than an absolute icteric thresholdvalue and if the blood plasma sample is not assigned to a lipemic classand is not assigned to a hemolytic class.
 14. The device according toclaim 13, wherein the first icteric wavelength is 470 nm.
 15. The deviceaccording to claim 1, wherein the predetermined set of classes comprisesan icteric class, the set of wavelengths comprises a first ictericwavelength in the range of from 450 nm to 485 nm and a second ictericwavelength in the range of from 510 nm to 520 nm, and the blood plasmasample is assigned to the icteric class if a ratio of the measurementvalue at the first icteric wavelength and the measurement value at thesecond icteric wavelength is less than a first relative ictericthreshold value.
 16. The device according to claim 15, wherein thesecond icteric wavelength is 515 nm.
 17. The device according to claim1, wherein the predetermined set of classes comprises a good class, andthe blood plasma sample is assigned to the good class if the bloodplasma sample is not assigned to a lipemic class, is not assigned to ahemolytic class and is not assigned to an icteric class.